This invention relates to truck/tractors and more particularly to a stop block for positioning a sliding fifth wheel at a predetermined location on its supporting racks.
1. Field of the Invention
Over-the-road, truck/tractor rigs of the eighteen wheel type are usually provided with a bracket assembly, commonly known as a "fifth wheel", mounted on the frame of the truck/tractor over the position of the dual wheel axle for supporting the forward end portion of the trailer.
The fifth wheel is supported by parallel racks for movement of the fifth wheel forward to rearward with respect to the position of the dual drive wheel axle for distributing the loaded trailer mass between the drive axle and the steering axle of the truck/tractor.
Air pressure operated detents in the fifth wheel unit engage the teeth of the racks to hold the fifth wheel against movement relative to the racks longitudinally of the truck/tractor. The spaces between the teeth of the racks are commonly referred to as "notches" and these notches are used as a reference in determining the distance the fifth wheel is to be moved forward or rearward to distribute the trailer mass between the truck/tractor axles.
For example, in one popular fifth wheel assembly, moving the fifth wheel one notch forwardly adds an additional 350 pounds (770 kilograms) to the front axle of the truck/tractor. The fifth wheel position relative to the racks is normally adjusted by locking the trailer rear wheel brakes, and moving the truck/tractor forward or backward in accordance with a desired position for the fifth wheel on the racks.
When the trailer is fully loaded, this is not easily accomplished and requires the driver getting in and out of the cab to check the position of the fifth wheel relative to the racks each time he has moved the truck/tractor relative to the trailer.
This invention solves the inconvenience of the driver not being able to easily and accurately move the fifth wheel to a desired position by providing a stop block for limiting movement of the fifth wheel.
2. Description of the Prior Art
As mentioned hereinabove, it is very difficult for a driver to stop a sliding fifth wheel at a desired notch along its racks.
Some drivers have used large bolts, long round bars, and even wrenches which sometimes lodge in and damage the racks in an attempt to stop the sliding fifth wheel at a desired notch. Such impromptu attempts have generally been unsatisfactory.
For example, the rod may bend and wedge between the rack and the fifth wheel unit and, in some cases, the trailer has been crashed into the sleeper compartment of the truck/tractor.
We do not know of any prior patents which discloses a stop block such as is disclosed by this invention.